Computer aided design (CAD) programs have allowed users to design various parts in “virtual” space before the parts ever reach a manufacturing stage. As CAD programs have become more powerful, parts modeled in “virtual” space (i.e., CAD models) have become more true to life. Often times, these CAD models are also referred to as three-dimensional (3-D) solid models or as solid models because of the fact that they are 3-D geometry pieces with solid properties, such as volume, faces that define the boundary of the three-dimensional solid geometry piece, weight, and so forth. Because the models have solid properties, solid features, such as solid featured forming patterns, may be incorporated into the solid models.
For example, a user may design a solid model of a speaker cover having small hole features arranged in a pattern to protect the delicate components while allowing sound to travel through the cover. Another example may be a solid model of a heatsink having fin features arranged in a particular pattern to increase the effective surface area for heat transfer. In both examples, the number of features forming the desired pattern may be numerous.
Often times, underlying these features are 2-D parametric sketches that geometrically define the features. For the example of small holes in the speaker covering, each of the small holes may be formed by a 2-D sketch of a small hole whereby the 2-D sketch of the small hole is extruded to perform a solid operation with the speaker covering. That is, the small hole is extruded and subtracted from the speaker covering forming the necessary holes. A change in the 2-D parametric sketch affects the solid model and vice versa.
Accordingly, during or subsequently, the user may change the design of the solid model, thereby affecting the surface on which the features may be patterned. In order to compensate for the change in the solid model, the user may be required to change the pattern of the features to ensure optimum utilization of the features. Furthermore, the user may change the design of the features themselves, thereby further affecting the pattern of the features.
Accommodating changes in design, in particular, the changes in design that affect the pattern of particular features may be difficult. For example, if the shape and/or size of the speaker cover is modified, the hole features that make up the pattern are required to be individually modified to ensure that the desired density of hole features is maintained within the boundary of the speaker cover. Modifying the hole features may involve individually modifying each 2-D sketch underlying the hole feature. Furthermore, the number of hole features may increase or decrease based at least upon the changes in shape and/or size of the speaker cover (i.e., the changes in the boundary of the patterned hole features). In the example of the heatsink, the pattern of the fin features may correspond to a desired effective surface area. Modifications in size and/or shape of the heatsink may affect the desired effective surface area because the boundary of the patterned fin features may change. However, in order to maintain the desired density of the fin features (i.e., the effective surface area), individual fin features may need to be modified in order to compensate for changes in the size and/or shape of the heatsink. Again, modifying individual fin features may involve modifying each 2-D sketch underlying each fin feature.
Parametric solid modeling capabilities of CAD programs may aid a user making necessary modifications to features and patterns in relation to design changes of a solid model. However, often times, correlating the features and the pattern with the solid model involves building numerous mathematical relationships between the features, in particular, the underlying 2-D sketches, the pattern, and the solid model. Building the numerous mathematical relationships may make designing features for a particular pattern very time consuming, and even minor errors in the mathematical relationships need to be corrected for the parametric solid modeling capabilities to function properly and provide the desired patterned results.
Often times, in order to reduce initial design time, a designer will forego building numerous mathematical relationships, and instead, proceed to design features and patterns without relationships on a solid model. However, if modifications of the solid model are desired, the designer may be required expend much more time to redesign the features, in particular, the underlying 2-D sketches, and patterns to accommodate the changes.